Buenos Aires (AFP) - An Argentine lawmaker was in a "critical condition" after being seriously wounded in a "mafia" shooting outside parliament in Buenos Aires on Thursday that left his civil servant companion dead.
Deputy Hector Olivares, 61, was taking a walk in the square outside the National Congress at 7:00 am (1000 GMT) with his friend Marcelo Yadon when they were ambushed from a car.
"He's in a critical condition. He's in danger, he's at risk. He underwent emergency surgery to avoid death," said Pablo Rossi, assistant director at the Ramos Mejia hospital treating Olivares.
Security Minister Patricia Bullrich said the attackers had the area under surveillance before striking.
"It's clear this is a mafia act," she said.
The legislator was hit with three bullets, his spokesman Hector Lencinas said, while Yadon, 58, took five rounds and died.
Olivares, a lawmaker in the governing coalition, is a member of the criminal legislation committee and was working on a football-related violence initiative.
Argentina's President Mauricio Macri vowed to catch the culprits.
Hours later, a relative of the owner of the gray Volkswagen used by the attackers was arrested, police sources said.
"The attackers shot Yadon as their main target and managed to kill him, and they could have killed Olivares, but they didn't," Bullrich said.
She released a video of the murder taken by a security camera.
The two victims can be seen shot at close range when passing by a parked car.
The video shows Yadon immobile on the ground while an injured Olivares walks a few meters (yards) seeking help.
Two attackers emerge from the car but don't finish off the lawmaker, with one leaving the area on foot.
Seconds later a police officer arrives at the scene and begins providing emergency first aid to Yadon, while just a few meters away the attackers' car slowly pulls away.
"We never received any threats of any type in the office. It's an open office where everyone is welcomed. (Olivares) was very calm," Lencinas told reporters.
Lawmaker Jose Cano called the shooting a "premeditated act."
"The information we have is that the car was parked half an hour before. They were waiting," Cano told television station Canal TN.
He said the two men shared an apartment close to where they were attacked and were childhood friends.
"I want to believe that it was a mistake. Olivares is an agricultural producer, a good man, a family man. We feel terrible," Julio Martinez, a senator in Olivares's home province of La Rioja, told Canal TN.